Electrical connector



ELECTRICAL CONNECTOR Original F iled Feb. 28. 1952 2 Sheets-Sheet 1INVENTOR 571/9040 Baez/mew Dec. 24, 1957 ELECTRICAL, CONNECTOROi'igina'l Filed Feb. 28, 1952 H. H. BURKHARDT 2,817,827

2 Sheets-Sheet 2 I NI 'EXTOR.

HA/P040 501965011907 A TTOR NE 1 United States Patent ()fiice 2,817,827Patented Dec. 24, 1957 ELECTRICAL CONNECTOR Harold H. Burkhardt,Greenfield, Mass., assignor to Millers Falls Company, Greenfield, Mass.,a corporation of Massachusetts Original application February 28, 1952,Serial No. 273,995, now Patent No. 2,662,434, dated December 15, 1953.Divided and this application April 13, 1953,

a Serial No. 348,378

2 Claims. (Cl. 339-252) This invention relates to reversing mechanismfor impact wrenches and the like.

An object is to provide a reversing mechanism which shall becomparatively simple in construction and efiicient in operation.

Other objects of the invention will in and will in part appearhereinafter.

The invention, accordingly, comprises the features of construction,combinations of elements and arrangement of parts, which will beexemplified in the constructions hereinafter set forth, and the scope ofthe application of which will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention,reference should be had to the following detailed description taken inconnection with the accompanying drawings, in which:-

Figure 1 is a longitudinal cross section.

FigureZ is a fragmentary rear end elevation view.

Figure 3 is a transverse section showing the parts in position fordriving the tool in one direction.

Figure 4 is a similar view showing the parts in the off or neutralposition.

.Figure 5 is an enlarged sectionon the line 5/5 of Figure 3.

Figure 6 is an end plan view showing the parts in position correspondingto that of Figure 4.

Figure 7 is a fragmentary section.

Turning now to the drawings, Figure 1 shows the tool as driven byelectric power with handle 1, and pivoted switch 2 for turning power onand off, as conventional in such tools.

The enclosing body of the tool is made up of three parts, 3, 4, and 5.Parts 3 and 4 are connected after assembly as by lead screw or screws 6,and the other end portion 5 is free to rotate about the central part 4,in order to change the direction of rotation of the driven tool, shownhere as a wrench 7, encircling bolt head 41.

Carried by central cover portion 4 as by screw bolts 9 are the fieldpole pieces of an electric motor of conventional design having armature10, and driving a shaft 11.

The outer end of this motor shaft is carried in a ball bearing mounting12, carried in a part 13, an extension of part 4, upon which is mountedpart 5 and held for rotation by cap screw 14.

The rotatable outer end 5 of the cover section carries a projection 15which engages a slot 16 in the rotatable part 17, which carries contactmembers 18 and 19 (see Figures 3 and 4). Upon rotating the part 5,contacts 18 and 19 may be changed from the position of Figure 3 to thatof Figure 4 and vice versa to determine the direction of rotation of theshaft.

This is shown clearly in Figures 3, 4 and 5 wherein contact members 18and 19 are connected to 17, and upon rotation pass under one end or theother of the part 33, and thereby reverse the direction of rotation ofthe armature 10. The part 33 is held yieldingly in part be obviousposition by springs 34 carried around the studs 35 adjacent the headthereof as shown in Figures 5 and 6.

Part 35 is provided near its other extremity with a bevel or chamferand, near the end, with an annular groove 47. Part 45 brush leadterminal shown in Figure 7 is provided with a round hole and slot, theround hole to permit insertion of the stud 35, and the slot of a widthsuitable to accept the small diameter of groove 47 in stud 35. Terminal45 is further provided with a stamped detent 46 to insure contact ofterminal 45 to stud 35 under all conditions except when removal ofterminal is desired. Groove 47 is of a width greater than height ofdetent 46. To attach terminal 45 to stud 35 it is only necessary todepress stud 35, compressing spring 34, and causing stud 35 to protrudebeyond insulating bushing 48. By placing terminal 45 so that stud 35enters the large round hole and terminal 45 is in line with groove 47 instud 35, a slight pull on lead wire will displace terminal 45 untilsmall diameter of groove 47 comes to rest at extremity of the slot.Detent 46 having passed through the groove comes to rest on the oppositeside of stud 35. Releasing pressure on head of stud 35, thereupon locksall members together securely, tension on stud 35 by spring 34 causingpressure on contact 33, and by reaction on terminal 45, with detent 46preventing any possibility of unintentional breaking of electricalcontact or mechanical disassembly of the parts.

It is to be noted that the two studs serve to lock the entire reversingswitch mechanism, making assembly and disassembly quick and easy withoutthe use of tools.

It is also to be noted that the reversing mechanism not only reversesthe brush connections, thereby reversing rotation of the motor, but itphysically translates the brushes into the commutating plane mostefiicient for that rotation of motor.

The commutator, brushes and other parts shown at the right of Figure lare of conventional design and are not further described.

The inner end of the shaft 11 is provided with teeth 22, meshing with aplanetary gear 23, which through the fixed gear 24 shown, drives theshaft 25. About this shaft 25 is carried weight 26 free to revolve aboutthe shaft 25 or to be displaced axially therealong. This weight 26 isdriven, in the construction shown, by two torsion springs A and B, eachof which has one end locked to the shaft 25 and the other end connectedto the weight 26. The weight 26 is provided on its forward extensionwith two radial lugs 36 and 37, provided with angular cam faces.

As shown, spring A is held to the shaft 25 by spring end engaged in slotin shaft as at 27. The outer end of spring A is held by stud 28 to theweight 26. This stud 28 as shown in Figure 1 is at the lower end of aslot 29 in weight 26. This causes an offsetting of the coils of thespring A as shown, thus preloading the spring A in compression andassuring firm contact of weight 26 to anvil 38 before camming occurs andrapid return of weight 26 after camming.

This is also true of the upper spring B which is connected by a stud 30resting in a short slot 31 while the connection at 32 to the shaft 25 isbelow the line of the stud 30, causing this spring also to be offset asshown.

The anvil 38 is provided with two radial lugs 39 and 40 with mating camfaces, and the anvil carries at its outer end the wrench 7, shown asdriving in this instance the bolt head 41. Figure 1 shows at 44 a springpressed ball end pin acting as a releasable connection between the anvil38 and the wrench 7.

The operation of this tool, as shown as a wrench, may now be followed.When the motor shaft 11 is revolv- 3 ing" at its predetermined speed,the weight 26, driven through the torsion springs A and B, after aslight lag due to its inertia, revolves at the same speed.

When, however, the anvil is caused to stop or decelerate as by the factthat the bolt is driven substantially home, it causes a similardeceleration or' stopping in the weight 26, the cams being engaged. Thedriving shaft, however, continues to rotate and torsional energy isstored in the springs. When the torque reaches a cer tain value, itcauses the cams to disengage. At the moment of disengagement, the weight26 rotates on the shaft 25 at the rotating velocity of the shaft 25 plustheenergy imparted to it by the energy stored in the spring. As thisspring energy is delivered to the weight 26, the compressive force ofthe spring is again asserted, and moves the weight 26 forward so thatit' causes its cam lllg's to strike thoseon the anvil with considerableimpact.

Thus it will be seen that inoperation by the switch 2, thewrench asshown is driven in one direction to run the bolt quickly home'andthereafter firmly set by the action of the spring control deviceshown. When this has been sufficiently accomplished, the power isreleased and the tool withdrawn.

When it is desired to turn the wrench in the opposite direction, whetherfor unscrewing a bolt or for screwing,

a left-handed bolt, as distinguished from the more usualright handed"bolt, the operator has only to turn the outer end member of the cover 5as by following the inscriptions- Rev. and Fwd. for reverse and forwardon Figure 2, and the operation is adjusted accordingly.

' It will thus be seen that I have provided a construction whichaccomplishes all the objects set forth above,

could be made without departing from the scope thereof, it is intendedthat all matter contained in the above description, or shown in theaccompanying drawings, shall be interpreted as illustrative and not in alimiting sense.

It is also to be understood that the following claims are intended tocover all of the generic and specific features of the invention hereindescribed, and all statements of the scope of the invention which as amatter of language might be said to fall therebetween.

This application is filed as a division of my application for ImpactTool, Serial No. 273,995, filed February 28, 1952, now Patent No.2,662,434, granted December 15, 1953.

I claim:

1. In an electric tool, a spring pressed stud, an annular groove at oneend of said stud, a brush lead terminal having a hole therein, and aslot of a width suitable to accept the diameter of the stud groove, adetent upon said terminal adapted to bear against the stud, but of awidth less than the width of the stud groove.

2. In anelectric tool, a spring pressed stud, an annular groove at oneend of said stud, a brush lead terminal having a hole therein, and aslot of a width suitable to accept thediameter of the stud groove, adetent upon said terminal adapted to bear against the stud, but of awidth less than the width of the stud groove, and a second similarspring pressed stud, diametrically opposite to the first stud.

